Perpetual calendar



FIG. 1 is a cross section view taken along section line 4-4 of FIG. 3;

FIG. 2 is a second perspective view thereof;

FIG. 3 is a top view thereof;

FIG. 4 is a cross section view taken along section line 4-4 of FIG. 3;

FIG. 5 is a side view thereof, the opposing side being a mirror image;

FIG. 6 is a front view thereof;

FIG. 7 is a back view thereof; and,

FIG. 8 is a bottom view thereof.

The broken lines shown in the drawings are included for purposes of illustrating portions of the perpetual calendar or for purposes of illustrating environment and form no part of the claimed design. 

CLAIM The ornamental design for a perpetual calendar, as shown and described. 